AutoFib2 : Small Fibres

摘要

In July 2001, AutoFib-2 (AF2), the prime focus robotic fibre positioner for the Isaac Newton Group's (ING) 4.2m William Hershel Telescope (WHT) had its new Small Fibre Module (SFM) successfully commissioned. The new SFM contains 150 science fibres and 10 fiducial bundles. Each science fibre has a diameter of 90 μm, which corresponds to 1.6 arcsec in the sky. The continuous science fibres are fed into the Nasmyth platform Wide Field Fibre Optic Spectrograph (WYFFOS). Each fiducial bundle, 450 μm in diameter, contains 10,000 coherent fibres providing a rough imaging capability over an 8 arcsec round field. This paper looks at the reasons for developing this module, examines its mechanical design, describes its new science and fiducial fibres, looks at the fibre alignment techniques used, explains the new guiding system and briefly discusses changes in the AF2 control system. It continues to reveal the results of some fibre characterisation experiments performed on sky and gives an example of a recent science run. The paper concludes with a section that lists planned AF2 enhancements.